Lyssavirus: Bat-borne disease in Australia


Caterina Klasen, Claudia Suttie,
Isabella Suttie, Daniel Tardo

Abstract

Australian Bat Lyssavirus (ABLV) is found in 1-7% of flying foxes, fruit bats and microbat species in Australia. ABLV is the only lyssavirus endemic to Australia and has caused at least 3 deaths since its identification in 1996.  ABLV is a single-stranded RNA virus belonging to the rhabdoviridae family, which includes other viruses such as the rabies virus. Transmission is usually via direct inoculation with infected saliva, commonly through a bite from a bat, or contact of infected saliva with mucous membranes. ABLV affects neural tissues, entering peripheral nerves at the site of exposure and travelling in a retrograde manner to the CNS. 

Clinical features of ABLV infection resemble that of encephalitic rabies including a agitation, hydrophobia, aerophobia and autonomic instability. Severe complications include asphyxiation, respiratory arrest and cardiac arrhythmias. Incubation period depends on host immune status and site of infection, with more rapid progression with exposure at sites of high innervation or on the face, neck or back, but is usually between 3-8 weeks. Once clinical symptoms are present, there is rapid deterioration and death within several days. All patients in Australia presenting with exposure to bat saliva should be managed for ABLV infection until proven otherwise. Wound sites should be washed thoroughly to inactivate the virus locally. For immunocompromised patients and patients never immunised with the rabies vaccine, management includes a series of rabies vaccinations and Human Rabies Immunoglobulin injection to the site of exposure. For previously immunised patients, only two rabies vaccines are required. We present the case of a two year old child who had an unwitnessed bite from a Corben’s Long-eared Bat. The child was treated as a possible ABLV case. The bat was subsequently tested and no ABLV was detected, so management for ABLV was ceased.